Cover title.; "Research"--Cover.; "June 25, 2004."; Includes bibliographical references (pages 201-206).; Final report;; Performed by North Carolina State University Dept. of Civil Engineering for North Carolina Department of Transportation...

"July 2006."; Includes bibliographical references (p. 56-57).; Final report;; Performed by the Department of Statistics, North Carolina State University and Moorman, Kizer & Reitzel Inc., and sponsored by North Carolina Department of...

"Report no. FHWA/NC/2002-015"--Tech. rept. doc. p.; Includes bibliographical references (leaves 19-20).; Final report;; Sponsored by the U.S. Dept. of Transportation, Research and Special Programs Administration; April 1999-June 2000.